The Cosmetic Ingredient Review Expert Panel (Panel) reviewed the safety of magnesium sulfate, which functions as a bulking agent in cosmetic products and is reportedly used at concentrations up to 11% and 25% in leave-on and rinse-off products, respectively. The Panel noted that the history of safe medical use of magnesium sulfate provides further confidence that there are no significant toxicity concerns relating to systemic exposure to this ingredient after cosmetic product application. Furthermore, the extensive clinical experience of the Panel, including the results of numerous patch tests, indicates that magnesium salts do not have the potential to induce sensitization. The Panel also noted that results were negative for 50% magnesium sulfate in a mouse skin irritation study and in an in vitro sensitization assay. The Panel concluded that magnesium sulfate is safe in cosmetics in the present practices of use and concentration described in the safety assessment.
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